The present disclosure relates to a position detection apparatus for detecting a position located on a detection surface as a position touched by an object of detection, the spatial position of the object separated away from the detection surface and a movement made by the object over the detection surface. By the object, a finger, a hand, an arm, a pen or the like is implied. In the following description, the object is also referred to as a ‘finger or the like.’
In addition, the present disclosure relates a display apparatus, which employs the position detection apparatus, and an electronic apparatus having such a display apparatus.
In the past, there have been known existing technologies for inputting information on a position touched by a finger or the like. The existing technologies include a special technology drawing attention in particular. In accordance with the special technology, there is provided a display apparatus capable of inputting information on the position of a button touched by a finger or the like as one of a variety of buttons appearing on a display screen in the same way as an operation to input information on the position of an ordinary button when the ordinary button is touched by the finger or the like. For more information on this special technology, the reader is advised to refer to Japanese Patent Laid-Open Nos. 2005-275644 and 2006-23904. By virtue of this special technology, the ordinary buttons can each be integrated in the display apparatus as a button displayed on the display screen, giving big merits that it is possible to reduce the space, which is occupied by the ordinary buttons and the display apparatus, as well as the number of components.
There are a variety of types of touch sensor for detecting a touch of a finger or the like. A typical example of a generally popular touch sensor is a sensor of an electrostatic-capacitance type. For more information on this sensor of the electrostatic-capacitance type, the reader is advised to refer to Japanese Patent Laid-Open No. 2006-23904. When a finger or the like is brought into contact with a touch panel, an electric field generated on the surface of the touch panel changes and can be detected as a change of the frequency of a current flowing to a detection electrode. Then, the sensor of the electrostatic-capacitance type detects the touch of the finger or the like as a change of the frequency.
That is to say, in accordance with the touch detection method described above, a change of an electric field generated on the surface of a touch panel is detected as a change of the frequency of a current flowing to a detection electrode. Thus, a finger or the like needs to be brought into contact with the surface of the touch panel or brought to a position sufficiently close to the surface. If the finger or the like is placed at a position far away from the surface of the touch panel or, to be more specific, if the finger or the like is placed at a position far away from the surface of the touch panel by a distance of 1 cm or a longer distance, no information is supplied to the touch panel. As described in Japanese Patent Laid-Open No. 2008-117371, however, even if the finger or the like is placed at a position far away from the surface of the touch panel, information can be supplied to the touch panel by for example changing the interval between detection electrodes adjacent to each other in accordance with the spatial position of the object which is the finger or the like. In accordance with Japanese Patent Laid-Open No. 2008-117371, the interval between detection electrodes adjacent to each other is changed by reducing the number of scanning detection electrodes.